Numerous devices have heretofore been produced for the tensioning of a running length of textile yarn. Further, certain of these devices have incorporated the use of a spherical element such as a ball which is received in a conical support through which yarn passes. The weight of the ball thus rests on the support, impeding the progress of yarn passing therebetween. These prior art devices have, however, been deficient for numerous reasons. For example, the majority of the devices are substantially enclosed, thus hindering feeding of yarn therethrough. Further, other of the devices are restricted to particular types of yarn. Still further, other devices operate on a principle different from that of the instant invention, though a yarn passageway and a spherical element are involved.
The present invention thus provides an improved yarn tensioning device over those of the prior art, wherein a spherical element resides on a seat and engages yarn passing therethrough so as to impede the progress of the yarn by a predetermined amount. The device of the present invention further possesses certain definite advantages over the prior art. For example, it is easily manufactured, threading of yarn is quite simple and quick; no surfaces are available for abrasion of the yarn or for collection of lint and slubs; and tension is automatically maintained without any adjustments after start up.
The prior art is devoid of any teaching or suggestion of the present invention. Exemplary of the prior art are U.S. Pat. Nos. 1,408,560 to Bingham et al; 1,432,399 to Land; 1,490,512 to Hill et al; 1,785,987 to Stewart; 2,373,513 to Stevenson; and 2,222,921 to Van Den Bergh.